Agricultural seeding machines use air pressure to meter and transport seed and agricultural chemicals. Pneumatic seed meters on row crop planters fall into two basic systems. In one system positive air pressure, that is air pressure which is greater than ambient air pressure, is used to meter the seeds. In the other system negative air pressure, that is air pressure that is less than ambient air pressure, is used to meter the seeds. An air pump is used to create the positive or negative air pressure. The air pump may be pneumatically coupled to an air pressure manifold. The air pressure manifold in turn is pneumatically coupled to the individual seed meters by an air hose. It is known to seal a transverse support beam or toolbar to form the air pressure manifold.
U.S. Pat. No. 4,843,983 discloses a quick pneumatic coupling for use in a folding agricultural planter comprising a rigid plastic funnel mounted to the end of a first conduit and a flexible and resilient rubber flange member mounted to a second conduit. The inner surface of the funnel forms a sealing surface which is contacted by the flange when it is inserted into the funnel. The coupling can be automatically coupled and decoupled by pivotally inserting and withdrawing the flanged member into and out of the receiving funnel